The union said Lewis received an "overwhelming 80 percent of the votes" cast, according to a preliminary tally of the as-yet unreleased votes.

"[Union members have] spoken ... saying that they appreciate the direction that the union has gone in this last three years, which is fighting for public education for everybody," Lewis said at a late night press conference at the union's headquarters at the Merchandise Mart.

Her challenger in the race was Chicago Public Schools counselor Tanya Saunders-Wolffe.

Looking forward to her next term, which begins July 1, Lewis called for a change in the conversation about public education.

"It cannot be a top-down mandate. It must be relevant to the people in the neighborhoods. It must be relevant in the choices that children have. There should be quality public schools in every single neighborhood," she said.

The Chicago Board of Education next week is expected to vote on a plan to shutter 54 schools in the nation's third-largest district. Lewis says the move is "racist" because it disproportionately affects students of color.